Recovery of copper minerals or values by froth flotation



Patented 12, 1933 RECOVERY OF COPPER MINERALS OR. A

. VALUES BY FROTH FLOTATION Reginald John Lemmon, Norton-on-Tees, England, assignor to Imperial Chemical In- Limited, a corporation of Great No Drawing. Application June 25, 1931, Serial 11330546318, and in Great Britain September 3,

1 Claim. (Cl. 209-167) This invention relates to the recovery of copfor example, as one of the reagents introduced per minerals or values from copper ores or prodinto the first or other flotation unit of a froth ucts containing copper minerals or values, and concentration apparatus, or the addition may be particularly to the recovery of copper minerals made to the ore pulp in a previous stage of its or values from so-called oxidized ores, by which preparation for flotation recovery, i. e. in the are meant copper ores in which the copper values procedure known as pre-treatment, or in such occur chiefly or to a substantial extent in chemiother manner as a preliminary trial test may cal combination with oxygen. Such oxidized show to be the more efiicient. ores, which may or may not include a proportion of copper values in chemical combination with Example sulphur, have hitherto been diflicult to'treat by r T froth flotation processes inasmuch as the copper A quant1ty of Rhodeslan copper ore, contaimng zlaltiiisogrggiolisreadily floated by the customary borniite (((lgscFejssLcmagtlclhite (CugO3.Chu(OH)f1),

I have now found that the revocery of copper azunp u u 2 all C rysoco minerals or values from oxidized copper ores can 5 52 26 23 i g g i g g? fg z f g g' be greatly improved by the use of cyanide blast furnace creosote being added in the pro pound as 'hereinafter defined, in conjunction 1 with one or more frothing agents, for example fi gg i g 9 122: g g gsgg g gggggg h knwn.and comntqnly used frothmg agents machine, with the further addition of cresylic with or without additional substances such as acid in the proportion of 1/6 pound per ton of those. known m h collectmg agents ore. A first froth concentrate was obtained presst1Sng agent's, dispersioni agents, or fons f which contained the bulk of the sulphide and agen e erm cyani e compoun as use herein and in the appended claim comprises only 2 :332 g gg g gg ggg s the the actualcyamdqs of the or alkalme P An addition of sodium cyanide was then made ammomum cyamde, and hydrocyamc acid 1tself. t h ul th f 1 d compounds may be used as 0: areas a 2625221112 as: gz g g figg g fi ggg :2 23 obtained which contained the bulk of the ammopounds present in or added to the ore pulp. It nium carbonate-soluble copper present in the ore. desired more thanone such cyanide compound A further addltlon 9 i 011 (1/6 pound per may be employed ton of ore) and cresyhc acid pound per ton The proportion of cyanide compound used is of ore) was then made to the pulp and av third usually small; it will t o t t dependent froth concentrate obta ned wh1ch contained the 85 upon the general nature of the ore and the progreater P of the resldllal copper Valuesportion of oxidized or sulphide minerals contained The assays of the Vanous concentrates were, therein, and may be from a fraction of one pound as per ton of ore, to two or more pounds (calculated 0 in terms of sodium cyanide), according to the duty it is required to perform. Preferably the 22%;? 2%; 3 proportion of cyanide compound employed is Wei ht Total in areas in are from V to 2 pounds per ton of ore, as we have Material per 5%, g 5 52 52 3 found that on the whole the best results are p cate um car- 5 obtained within these limits. We have found minerals bonate that recovery is to a certain extent impaired if Crude ore 100.00 2'. 06 0.68 1 as greater proportions of cyanide compound are em First concentrate L M 36 93 3 37 p y ds c l d conceliltlgteu g. 13. g 3. g 1; 5% concen ra e The addition of the cyanide compound may Tamngs 87' 0. 0.11 0 54 o be made to the flotation circuit in various ways,

The per cent recoveries eflected were thus as follows:-

Copper Copper T on tiff-3 P 13? in o s p 1 e so u Mater copper and 5111- ammonicate um carminerals bonate Crude ore 100. 0 I 100. 0 100. 0 First concentrate. Z3. 4 65. 1 2. 9 Second concentrate 38. 7 13, 6 5i. 0 Third concentrate- 10. 2 6. 8 l1. 9 Tailings 27. 6 14. 1 34. 1

It will be noted that the recovery of total copper before the addition of sodium cyanide was very low, and that the addition of sodium cyanide resulted in the recovery of a substantial amount of the oxidized copper minerals, together with a further amount of copper as sulphide.

\ Example 2 A quantity of copper ore, containing bomite, malachite, cuprite (C1120) and native copper, in a siliceous gangue, was wet-crushed to 80 mesh 1. M. M. to form a pulp of 1:5 water-solid ratio,

with the addition in grinding of one-eighth of 'one pound of sodium cyanide, one-quarter of one pound of blast furnace creosote, one-twelfth of one pound of pine oil, all per ton of ore. The resulting pulp was treated in a sub-aeration flotation machine, and a first froth concentrate obtained, assaying as given below. An addition of one-half of one pound of sodium cyanide, onethird of one pound of blast furnace creosote, and one-third of one pound of pine oil, all per ton of ore, was then made in the machine, and a second froth concentrate obtained.. The assays of the two concentrates and tailings were as follows:-

Per cent. 7 Total Weight solub e in Material copper per cent per cent ammum 21131:- bonate Crude ore 100. 0 3. 60 3. 36 First concentratel. 0 30. 67 26. 49 16. 0 16. 60 15. 76 83. 0 0. 77 0.70

By way of comparison with the above procedure, the following results were obtained by froth concentration without the use of cyanide:-A similar sample of ore to 'that employed above was wet-ground to 80 mesh I. M. M. to form a pulp of 1:5 water-solid ratio, with the addition in grimgng of one-quarter of one pound of blast furnace creosote and one-twelfth of one pound of pine oil, both per ton of ore. The resulting pulp was treated in a sub-aeration flotation machine and a first froth concentrate obtained, assaying as given below. An addition of one-third of a pound of pine oil, and one-third of a pound of blast furnace creosote, both per ton of ore, was then made in the machine, and

a further froth concentrate obtained. The assays of the two concentrates and tailings were as follows:

Per cent Total f, Weight sold 0 in Material 1 1 w w rm! bonate Crude ore 100. 0 3. 26 2. 96 First concentrate 2. 0 25. 65 19. 18 Second concentrate- 3. 25 16. l1 13. 14 Tailings 94. 75 2. 43 2. 20

The per cent recoveries effected were thus as follows Co M a 1 1 E? a r a amm copper um carbonate Crude ore 100. 0 100. 8 14. 5 l3. 0 15. 0 l4. 4 Tailings- 70. d 72. 5

It will be noted that poor recoveries were obtained both in the case of thetotal copper (including .bornite) and also in the case of the soluble copper constituent.

From the above figures it will be observed that the addition of sodium cyanide had a marked influence upon both the flotation of the total and soluble copper in the pulp, resulting in the substantial recoveries, severally, of 82.1 per cent total copper, and 82.8 per cent soluble copper;

Corresponding recoveries without sodium cyanide were 29.5 per cent total copper and 27.4 per cent soluble copper.

In the case of minerals such as those treated in the above examples, which contain both sulphide and oxidized ore, it is preferred to perform I a preliminary flotation'without cyanide, or with a relatively small quantity of the same, for the purpose of removing the bulk of the relatively easily floated sulphide and to float the remaining oxidized ore with the aid-of a cyanide compound as described.

I am aware that in the froth concentration of mixed sulphide ores containing iron sulphide the addition of cyanide has been suggested for the purpose of effecting differential flotation of the sulphides through the depressing action of the cyanide upon the flotation of iron sulphide, but the present invention makes use of an entirely different principle, namely the efficiency of cyanide compounds as reagents whereby oxidized copper minerals or compounds, not otherwise readily floated, are rendered amenable to' froth Various changes may be made in the method of carrying out my invention and I do not desire to be limited to the procedure hereinbefore set out, except as defined in the following claim.

I claim:

A process for the recovery of copper values from copper ores in which the values occur both in chemical combination with oxygen and as sulphide, said ores being substantially free from gold or silver, which comprises subjecting the crushed ore to froth concentration in stages in REGINALD JOHN LEMNION. 

